Jack Davis: greeting card original art (1960’s)
Frank Brunner: Warp #3 cover original art (1983)
Jerry Grandenetti: The Spectre pin-up (1975)
Stan Drake: The Heart of Juliet Jones original art (1956)
Michael W. Kaluta: “The Shadow and his li’l pals: The Galactic Girl Guides" sketch (1988)
Joe Kubert: Tales of the Green Beret original art (1967)
Doug Wildey: Wyatt Earp #28 original art (1959)
Doug Wildey: Twisted Tales #3 original art (1983)
John Cullen Murphy: Big Ben Bolt original art (1959)
Steve Ditko & Eric Stanton: Merry Mixup, the Madcap Model original art.
Though signed only by Stanton, the lettering and (at least) the faces are definitely Ditko.